The present invention relates generally to temperature measuring devices, and more particularly to such a device for measuring the temperature of a surface, the device being in the form of a probe so that the indicating portion of the meter is substantially spaced away from the workpiece or sample whose temperature is being measured.
In the preferred form of the invention hereinafter described and illustrated, there is provided a body comprising an elongated tubular stem in which an elongated spindle is concentrically mounted and rotatably journaled. The lower end of the spindle has fixed thereto the central portion of a spiral bimetallic strip, the lowermost end of the spindle constituting a tip spaced slightly below the lower edge of the spiral strip. The outermost turn of the strip is provided with an outwardly extending tab, and means are provided for restraining angular movement of the tab relative to the stem, while permitting limited axial movement of the tab relative to the stem. The upper end of the spindle carries thereon an indicating pointer, which visually cooperates in indicating temperature with a dial fixed to the upper end of the stem. Resilient means may be provided for biasing the spindle and the parts carried thereby downwardly relative to the stem, as well as means for limiting that downward movement. The lower end of the stem desirably has fixed thereto a downwardly open cup-shaped shield surrounding the bimetallic strip. In the rest position of the parts, the lowermost end of the spindle extends slightly below the lower edge of the cup-shaped shield, as does also the lowermost edge of the spiral strip. In measuring the temperature of a sample, the lowermost tip of the spindle is placed on the sample, and the user, grasping the instrument at the upper end of the stem, moves the stem and parts carried thereby slightly downwardly or toward the sample until the lower edge of the shield contacts the sample.
Accordingly, it is a principal object of the present invention to provide and disclose a novel surface thermometer including an elongated stem so that the user's fingers, grasping the stem, are substantially spaced from the sample and thereby protected from being harmed by the heat of the sample. Other objects and purposes are to provide, in such a thermometer, a spiral bimetallic strip carried on the lower end of a spindle rotatably mounted in the elongated tubular stem and permitted slight axial movement relative to the stem; to provide such a device having a lower cup-shaped shield for partially surrounding the spiral bimetallic strip for protecting the same; to provide in such a device resilient means for biasing the spindle and the parts carried thereby downwardly relative to the tubular stem, and means limiting such downward movement; and for other and additional objects as will be understood from the following description of the preferred embodiment of the invention, taken in connection with the accompanying drawing.